Q2
I think Peter is telling his readers about the wonderful gift that they've received through Christ Jesus. In this verse, Peter informs them that they lack nothing because everything they need for life, earthly and eternal, and for godliness has been provided for them. Too often we neglect to fully accept the complete gift of salvation that we have in Christ Jesus. We only receive parts of it.
It is difficult for one to live a godly life apart from God. For this very reason, God sent us the comforter, the Holy Spirit, that would guide us into all understanding and truth. This verse begins, "His divine power has given us." Therefore, if we surrender and submit to the authority, guidance, and teaching of the Holy Spirit, then we will be able to walk confidently and participate in the precious faith that we received.
One must know God in order to participate in this promise. If one has not established an intimate relationship with God, he/she will never profit from the provision that God has ordained for his children. Once one comes into the knowledge of God, to know, intimately God, then he/she is able to benefit from all the promises that God's Salvation offers. It is not enough to know about God, one must truly KNOW him.